Surgical stapling device

ABSTRACT

A surgical stapler comprises an elongate housing  10  and a surgical staple  14  slidable longitudinally within the housing towards the free forward end thereof. The back  18  of the staple has a rearward extension  22.  An actuator  16  is slidable forwardly within the housing for driving the staple towards the free end of the housing. An upstanding flange  30  on the extension  22  engages a stop  32  within the housing to restrain the back of the staple against forward movement of the actuator bends the staple to bring the free ends of the legs towards one another to close the staple. Further movement of the actuator then ruptures the join between the extension and the back of the staple to release the closed staple.

FIELD OF THE INVENTION

This invention relates to a surgical stapling device.

BACKGROUND

Surgical stapling devices have been in existence for many years. Theyare routinely used in surgical procedures mainly for the purposes ofeffecting a wound closure. Some of the most popular applications includeclosing a skin incision end-to-end or end-to-side anastomosis ofinternal (generally tubular) vessels such as the large bowel, etc.Current staplers are designed to deliver one or more staples in a serialfashion or a number of staples in one shot. Skin staplers, for example,deliver 30 or more staplers in a serial fashion. The staples are stackedwithin the device and during the firing operation one staple is advancedfrom the stack and delivered through the head of the device. During thefollowing cycle another staple is advanced from the top of the stack andagain delivered through the head of the device and so on. In one shotdevices such as a bowel anastomosis stapler the staples are prearrangedin a linear or circular fashion and upon activation of the device allthe staples are delivered through the head. Examples of existing priorart as described above include U.S. Pat. Nos. 4,592,498, 5,289,963,5,433,721 and 5,470,010.

The mechanism involved in forming a staple and releasing it from itsforming mechanism is common to the majority of surgical stapler devices.Generally the components include an anvil, a staple closing actuator,and a staple release mechanism. The anvil is normally positioned infront of the staple and the actuator directly behind the staple. As theactuator advances the staple against the anvil the back section of thestaple deforms around both ends of the anvil thereby transforming thestaple from a generally U-shape to a generally rectangular shape. Atthis point the actuator generally retracts and the staple is releasedfrom the anvil either as a result of the anvil moving out of positionand allowing the staple to move forward, or alternatively ejecting thestaple over the anvil thereby releasing it from the device.

There are a number of problems associated with the mechanism asdescribed above. Firstly, as the anvil is normally positioned in frontof the staple it naturally becomes trapped between the back of thestaple and the tissue into which it is being delivered causing thestaple back to be spaced away from the tissue as opposed to lyingtightly on its surface. This is a particular problem in the field ofvascular puncture closure when it is desirable to keep the legs of thestaple as short as possible so as to avoid having the legs of the staplewithin the vessel lumen.

Secondly, the method of releasing the staple from the anvil can be bothcomplicated and unreliable. Metal springs are normally used which ejectthe staple over the anvil thereby affecting its release. However, shouldthe spring fail to operate or is prohibited from operating properly byvirtue of some tissue blockage etc, the device will become trappedin-situ.

Alternative release mechanisms include mechanical means of moving theanvil so that it is no longer in the path of the staple as it releasesfrom the device. Again this generally involves very small metalcomponents with relatively small movements which can fail to operatethereby leaving the staple trapped within the device and attached to thetissue into which it has been delivered.

Therefore there is a need for an improved surgical stapling device whichwill facilitate closer approximation of the staple back onto the surfaceof the vessel into which the staple is being delivered and a method ofdeforming the staple which does not include the use of an anvilcomponent and therefore will not require the use of other components ormechanisms to facilitate the release of the staple from the anvil.

SUMMARY OF THE INVENTION

According to the present invention there is provided a surgical staplingdevice comprising an elongate housing, a surgical staple slidablelongitudinally within the housing towards a free forward end thereof,the staple having a back and two forwardly pointing legs, an actuatorslidable forwardly within the housing for driving the staple towards thefree end of the housing, means for restraining the back of the stapleagainst forward movement beyond a predetermined point such that furtherforward movement of the actuator bends the staple to bring the free endsof the legs towards one another to close the staple, and means forreleasing the closed staple, wherein the back of the staple has arearward extension and the restraining means comprises means forrestraining the extension.

In a preferred embodiment the rearward extension is rupturably joined tothe back of the staple, the staple being released by forward movement ofthe actuator beyond the point at which the staple is closed while theextension is restrained, thereby to rupture the join.

In another preferred embodiment a rearward extension is created which isintegral to the staple back. This rearward extension creates a slot intowhich one end of an extension component is connected. Once the formerhas formed the staple around the anvil the extension is released fromthe staple during rearward movement of the former.

The benefits of the invention over conventional stapling devices isthat, firstly, as no anvil is required the staple can be advancedforward to a position where the staple back is in direct contact withthe tissue being stapled. This is of particular advantage when thestaple legs must remain short but the level of penetration into thetissue must be assured. Secondly, because there is no anvil componentinvolved in the delivery mechanism, there is no requirement to addadditional components so as to facilitate ejection of the staple over oraround the anvil component or alternatively to move the anvil componentto a position which allows the staple to advance forward and free up thedevice.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a staple with a restraining plate foruse in an embodiment of the invention;

FIGS. 2( a) to 2(d) are plan views (left hand column) and equivalentsectional views (right hand column) of a stapling device according tothe embodiment in successive stages of operation;

FIG. 3 is a perspective view of the staple and actuator assembly of FIG.2;

FIG. 4 is a perspective view of the forward tip of the actuator of FIG.2; and

FIGS. 5 to 12 are perspective view of further embodiments of staple foruse with a device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings the same reference numerals have been used for the sameor equivalent parts.

Referring to FIGS. 1 to 4, a surgical stapling device comprises anelongated housing or shaft 10 having upper and lower halves 10 a and 10b defining between them a longitudinal channel 12 for slidablyaccommodating a staple 14 and a staple closing actuator 16 (in the planviews in the left hand column of FIG. 2 only the lower housing half 10 bis shown). Only the free forward end of the housing 10 is shown in thedrawings, since that is where the invention lies in the presentembodiment. The rear end of the housing 10 is preferably formed with apistol grip and the movement of the various components to be describedmay be effected by a trigger acting through a cam system. Such anarrangement is described in Irish Patent Application S2000/0722 whichmay be readily adapted to operate the device of the present embodiment.

The staple 14 is generally U-shaped, having a back 18 and two forwardlypointing legs 20. The free ends of the staple legs 20 are sharpened forease of tissue penetration. Integral with the staple back 18 there is arearwardly extending plate 22 which is attached to the upper edge of thecentre section 18 a of the staple back by a pair of narrow, relativelyweak tabs 24. The tabs are effectively thin metal bridges which connectthe staple back to the plate 22. At the rear end of the plate 22 thereis an upstanding flange 30 perpendicular to the plane of the plate 22.In this embodiment the staple 14 including the plate 22 and flange 30 ismade as an integral structure from stamped and bent sheet metal stock,for example, a malleable metal or metal alloy such as stainless steel ortitanium.

Adjacent to the tabs 24, at the junctions 26 between the centre section18 a and the outer sections 18 b of the staple back on either side, andwhere in use the staple back is designed to bend through an angle of 90°as will be described, local deformation of the material of the staple isprovided so as to ensure that bending takes place preferentially atthose points.

The actuator 16 is an elongated rod having a forward end which is forkedto provide two arms 28 separated by a recess 34. The lateral separationof the arms 28 is slightly greater than the distance between thejunctions 26 on the back 18 of the staple.

The device is assembled (FIG. 2) with the actuator 16 extendinglongitudinally in the channel 12 with its forked end facing towards thefree forward end of the housing 10. The staple 14 is positioned freelyin front of the actuator 16 with its back 18 transverse to the axis ofthe housing 10 with the plate 22 extending rearwardly across the topsurface of the actuator. The flange 30 extends up into a recess 32 inthe top housing half 10 a. The actuator arms 28 are behind and inalignment with the outer sections 18 b of the staple back.

In use, both the staple 14 and the actuator 16 are initially retracted,FIG. 2( a), so that the flange 30 is adjacent the rear end of the recess32 and the entire staple 14 is contained wholly within the housing 10.Upon operation of the trigger previously mentioned, or other operatingmechanism, the actuator 16 is driven forwardly towards the free forwardend of the housing 10. This drives the staple 14 before it by engagementof the actuator arms 28 with the outer sections 18 b of the staple back.

At a predetermined point, FIG. 2( b), where the back of the staple issubstantially level with the forward end of the housing 10, the flange30 comes up against the front end of the recess 32. The flange 30 andfront end of the recess 32 act as cooperating stop means which, via theplate 22, restrain the centre section 18 a of the staple back againstfurther forward movement. Thus, as the actuator 16 continues to advance,the actuator arms 28 bend the outer sections 18 b of the back of thestaple forwardly through 90° to bring the free ends of the staple legs20 towards one another and deform the staple into a generallyrectangular closed shape, FIG. 2( c).

At this point the base 36 of the recess 34 in the front of the actuator16 is abutting against the centre section 18 a of the staple base. Now,since the plate 22 remains restrained by engagement of the stop means30/32 further forward movement of the actuator 16 will rupture the tabs24 thus freeing the staple from the plate 22. At this point the cycle iscomplete.

FIG. 5 shows an alternative embodiment for the staple. It comprises astandard round wire staple 40 having a rearwardly extending restrainingplate 22 with upstanding flange 30 attached to the centre section of thestaple back by rupturable tabs 24. The tabs may be attached to thestaple back by soldering, braising, laser welding, adhesive bonding,etc. The preferred process will ensure a consistent break-off forcebetween the tabs and the staple back.

Referring now to FIG. 6, another embodiment of the staple is shown whichincludes two staples 14 disposed spaced apart one above and each havinga respective rearwardly-extending restraining plate 22 joined thereto byrupturable tabs as previously described. In this case the rear ends ofthe parallel plates are joined by a common flange 30. In such a case thestapling device would be modified such that stop means on the housing 10projected into the space between the upper and lower plates 22 andengaged the flange 30 between them to restrain the back of the staple.The double staple could be driven by two actuators 16, one disposedabove the upper plate 22 and the other below the lower plate 22, or asingle actuator could be used having upper and lower branches whichembrace the plates 22 between them.

FIG. 7 shows another staple usable in the invention in which the centresection 18 a of the staple back is enlarged, for example by forming itas a disk 42, so that the centre section 18 a has a much greater area ina plane normal to the longitudinal axis of the housing 10 than either ofthe outer section 18 b. This configuration has particular application inthe field of vascular puncture closure. The process of closing punctureholes using conventional staples may be enhanced using this method asthe disk 42 on the staple back provides greater surface coverage of thepuncture hole area thereby effecting haemostasis in a shorter time.

FIG. 8 shows a configuration which is essentially the double staple asdescribed in FIG. 6 but for use in combination with a stapling devicehaving a locator tube 44. The locator tube 44, which passes between theplates 22 through a hole (not shown) in the flange 30, is slidableaxially within the housing 10 between a forward position wherein itprojects beyond the free forward end of the housing 10 to enter apuncture site in a liquid-carrying vessel in a human or animal, therebyto locate the free end of the housing at the puncture site, and arearward position wherein the locator tube is retracted into thehousing. In use a guidewire (not shown) extends within the locator tubeand emerges from the forward end of the tube, the tube 44 being trackedalong the guidewire to the puncture site and the guidewire and tubebeing retracted into the housing prior to closure of the staples. Alocator tube is described in the aforementioned Irish Patent ApplicationS2000/0722, and it will be clear to one skilled in the art how to modifythe embodiment shown in FIG. 2 to incorporate such a tube. Thisconfiguration has particular relevance in the area of vascular punctureclosure.

The staple configurations shown in FIGS. 6 to 8 are, like the stapleshown in FIG. 1, designed so that they are easily manufactured asintegral structures from sheet metal using a conventional metal stampingand bending processes.

The embodiment of staple shown in FIG. 9 comprises a staple essentiallyas described with reference to FIG. 7 but without the attached plate 22.Instead, a rearwardly extending filament 46 is attached to the rearsurface of the disk 42. In use, the stapling device is adapted to trapor hold the rear end of the filament 46 so that it becomes taut at thepoint where the staple back is level with the front end of the housing10 so that further advance of the actuator will bend the outer sections18 b of the staple back to close the staple as previously described. Atthis point the actuator may advance further forward thereby shearing ordetaching the filament from the back surface of the disk 42.Alternatively, the actuator may retract while simultaneously the devicereleases the filament at its rear end and consequently releasing thestaple from the device. Examples of the filament material are Dacron,PLA, PGA and PLGA.

In FIG. 10 a staple configuration is shown similar to that in FIG. 3except that the rupture tabs 24 are replaced with a slotted tab 50 whichengages with an upstanding flange 52 integral to plate 22. As the formeradvances forward to form the staple the back is held in position by theplate 22. Once forming is complete the former component retracts whilesimultaneously causing the plate 22 to move down disengaging the flange52 from the staple slot 50 allowing it to separate from the staplerdevice.

FIGS. 11 and 12 illustrate further embodiments of this principle. InFIG. 11 the flange 52 engages a band 54 which is formed integrally withan lies parallel to the back 18 of the staple. In FIG. 12 a pair ofL-shaped cylindrical arms engage a channel section 58 of the staple back18 to restrain the staple during forming. When forming is complete theformer retracts while simultaneously causing the arms 56 to be pushedoutwards, away from one another and out of engagement with the channelsection 58.

The invention is not limited to the embodiments described herein and maybe modified or varied without departing from the scope of the invention.

1. A surgical stapling device, comprising: an elongate housing; asurgical staple slidable longitudinally within the housing towards afree forward end thereof, the staple having two forwardly pointing legsand a back having a rearward extension; an actuator slidable forwardlywithin the housing for driving the staple towards the free end of thehousing; means for restraining the rearward extension on the back of thestaple against forward movement beyond a predetermined point such thatfurther forward movement of the actuator bends the staple to bring thefree ends of the legs towards one another to close the staple; and meansfor releasing the closed staple.
 2. The device of claim 1, wherein therearward extension is rupturably joined to the back of the staple suchthat the staple is released by forward movement of the actuator beyondthe predetermined point at which the staple is closed while theextension is restrained.
 3. The device of claim 1, wherein the back ofthe staple is disposed substantially transverse the longitudinal axis ofthe housing and the two forwardly pointing legs extend at an angle fromopposite ends of the back, the back of the staple having a centersection and two outer sections, the actuator engaging the outer sectionsof the back of the staple and the restraining means restraining thecenter section of the staple back such that further forward movement ofthe actuator bends the outer sections of the back of the stapleforwardly relative to the center section.
 4. The device of claim 3,wherein the back of the staple is adapted for preferential bending atthe junction between the center and outer sections.
 5. The device ofclaim 3, wherein the center section of the back of the staple has agreater area in a plane normal to the longitudinal axis of the housingthan the outer sections.
 6. The device of claim 1, wherein the extensionextends rigidly from the staple back and has a stop means which comes toabut against a cooperating stop means within the housing when the backof the staple reaches the predetermined point.
 7. The device of claim 1,wherein there are two staples disposed spaced apart one above the otherand each has a respective rearward extension, the rearward extensionsbeing connected together and both staples being driven forwardly andclosed simultaneously by at least one actuator.
 8. The device of claim7, further including an elongated locator member slidable axially withinthe housing between a forward position wherein the locator memberprojects beyond the free end of the housing to enter a puncture site ina liquid-carrying vessel in a human or animal, thereby to locate thefree end of the housing at the puncture site, and a rearward positionwherein the locator member is retracted into the housing, the locatormember passing between the two rearward extensions and being retractedinto the housing prior to closure of the staples.
 9. The device of claim8, wherein the locator member comprises a hollow tube and a guidewireextends within the locator tube and emerges from the forward end of thetube.
 10. The device of claim 1, wherein the staple and rearwardextension are made as an integral structure by stamping and bending ametal sheet.
 11. A surgical stapling device, comprising: an elongatehousing adapted to slidably receive a surgical staple and to drive astaple forwardly to a predetermined position at which an extension onthe staple is effective to restrain the staple to the predeterminedposition and further forward movement of the staple is effective to bendat least one leg on the staple and to release the staple from theextension.
 12. The device of claim 11, further comprising an actuatorslidable longitudinally within the housing for driving the stapleforwardly.
 13. The device of claim 11, wherein the extension isrupturably joined to the staple.
 14. A method for closing a puncturewound in tissue, comprising: positioning a forward end of an elongatehousing adjacent to a puncture wound in tissue; advancing an actuatorforwardly through the elongate housing to advance a staple to apredetermined position, the staple having a restraining means forrestraining the staple against further forward movement; furtheradvancing the actuator forwardly to move at least one leg on the stapleto close the staple, and to release the staple from the restrainingmeans.
 15. The method of claim 14, wherein the at least one leg of thestaple extends through the tissue adjacent the puncture wound and a backof the staple is positioned in direct contact with the tissue when thestaple is in the predetermined position.
 16. The method of claim 14,wherein the restraining means comprises an extension extending from aback of the staple, the extension being rupturably joined to the back ofthe staple to release the staple therefrom.